Features of the contact metamorphism in ores of the Novo-Uchaly deposit, South Urals

The article presents the impact of contact metamorphism on the ores of the large Novo-Uchaly Cu-Zn massive sulfide deposit (South Urals) as well as structural features of the contact zone and change in mineral composition of the ore and dikes. The study of contact metamorphism is also of practical interest because the ores are enriched in precious metals and rare elements in the local contact areas. The author together with geologists from the Uchaly Mining and Processing Plant carried out a geological and mineralogical mapping of the deposit (underground mine). The analytical studies were based on using optical and scanning electron microscopes. The results of detailed geological mapping are as follows: the thick gabbro-diorite dike is alterated by chloritization, hematitization and silicification, and contains quartz-carbonate-sulfide veinlets. The exocontact zones are usually thin, with thickness less than 10 cm, rarely reach 2 m. The signs of the contact metamorphism of the ores: cataclasis, recrystallization of sulfides; the appearance of the increased amount of rare minerals (magnetite, fahlore, galena); violation of the geochemical zoning caused by local redistribution of chemical elements. These factors characterize the ore transformation by the processes - local contact metamorphism and the subsequent hydrothermal mineralization caused by the remobilization of the ore substance.